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J. FIMEHEN. METHOD OF MAKING TURBINE NOZZLE STRUCTURES. APPLICATION FILED MAY 18. IBM}.

1,307,786. Patent-ed June 24, 1919.

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JOHN F. METTEN', or PHILADELPHIA, riiNNsYLIvANiA,AssIGNon TO THE WILLIAM CRAMP & soNs siirra ENGINE BUILDING coMrANY, A CORPORATION on PENN- SYLVANIA.

Specification of Letters Patent. Patented June 24, 1919.

Application filed May 18, 1918. Serial No. 235,275.

To all whom it mag concern:

Be it known that I, JOHN F. Mnr'iEN, a citizen of the United States, residing at Philadelphia, in the county of Philadelphia and State of Pennsylvania, have invented certain new and useful Improvements in Methods of Making Turbine-Nozzle Structures, of which the following is a specification.

The principal object of my invention is to provide a new and improved method of constructing nozzles for turbines. Another object of my invention is to provide a which my invention maybe practised'aside from the particular way herein disclosed.

The improved construction obtained by my new method is specially adaptable to nozzles of the initial ahead stage or reverse I stages of marine turbines where the pressure drop and expansion ratio are fairly large. Heretofore it has been common to make such nozzles by cutting the passages from solid or partially cored castings, or by casting plates of proper shape into the material forming part ofthe nozzles. With a pure cast nozzle the partitions dividing adjacent channels are subject to breakage due to initial casting strains. Withthe castin plate type the surfaces of the passages are difficult to finish properly and accurately, and there is also the possibility of breakage due to defective castiiig-in of the plates. In the method herein disclosed the nozzle is formed from wholly machined parts, free from. all inherent castingtrou bles, and can be fastened as a unit to a turbine casing or diaphragm in any approved manner.

Briefly outlined, the method involves form ing plain rings, machining these in aboring oblique to the corresponding plane containing the axis, next the nozzle rings are slotted I in the same direction in which the tool was I will now give a specific description of one sequence of operations that exemplify my invention. I

Figures 1 and 2 are elevations of bars of steel from which the rings are to be formed;

Figs. 3 and 4: are corresponding cross-sew tions with certain diagrammatic indications thereon tobe referred to later;

Fig. 5 15 a plan view of a boring mill'table with the rings thereon at a certain stage in the process of manufacture;

Fig. 6 is a section taken on the line 6 in Fig. 5;

Fig. 7 is a cross-section taken on the line 7-8 in Fig. 6 before a certain cut is made,

Fig. 8 is a corresponding section after that same cut has been made;

Fig. 9'is an elevation of the external ring in a saddle in: position for slotting;

F g. 10 is a section on the line 10 in Fig. 9; Fig. 11 is a top plan view as indicated by the arrows designated 11 in Figs. 9 and 10: 0 Fig. 12 is an elevation for the internal ring corresponding to Fig. 9 for the external ring; I

Fig. 13 is a fragmentary elevation of the completely assembled nozzle structure;

Fig. 14 is a developed section taken on the curved line ll-14: of Fig. 13.

Fig; 15 is an edge view of one of" the blades, and I Fig. 16 is a face view of the same blade. Two bars of steel 21 and 22 of appropriate length are bent to the proper curvature and fastened to the rotatablebed 23 of a boring mill. The attachment is not made directly, but the boring mill bed 23 carries two curved bars 24: and25 each of Z-section which are fastened to the bed 23 by the 1 studs 26 in such a way as to leave a? slot 58 between them. The bars 21 and 22 are tapped as at 27 and are fastened tothese members 24 and 25 by the studs 28.

1 The external portions 33 and 34 (Figs. 3 and4 are cut away by boring in the ordlnary manner by means of a tool fed in a plane containing the axis of the ring. The ring 21 is formed in this way with the wide fiange 40, the narrow flange 38 and the web 39 between them. In a corresponding way the ring 22 is formed with the wide flange 37, the narrow flange 35 and the web 36 between them.

The space between the two rings 21 and 22 is a little narrower than the intended width of the nozzle openings, prior to mak ing the out between them now to be described. The tool 29 is made to cut just that width. It comprises a shank 30 with a head 31, the cutting edges being at 32. This tool is fed in the direction indicated by the line A B C shown in Figs. 5 and 6, the work being rotated in the direction of the arrow D. The tool is shown at 29 just as it-is about to begin'its first cut and at 29" after ithas been fed clear through in the direction A B C and has completed its out, at which time the cutting head 31 sticks down into the slot 58 between the members 24 and 25. The portion cut away from the ring 21 is indi cated by the numeral 45 in Fig. 3 and similarly the portion cutaway from the ring 22 is indicated by 46 in Fig. 4. As the tool 29 advances in the direction A B C, its distance from the boring mill axis 59 increases, as is evident from Fig. 5,'so that the last part of the cut is on a greater radius and the ring 21 will be undercut as viewed in 5. The nozzle lining surfaces 47 and 48 are curved and the elements made by a section, the plane of which contains the axis, are curved as shown in Fig. 8. However, the elements parallel. to the line A B C are straight asis-evident from the manner in which'the surfaces are formed by the tool 29. From a geometrical point of view, the surfaces 47 and 48 might be formed by giving the tool 29 a reciprocatory cutting motion along the line A B C and feeding the work by stepped rotation in the direction indicated by the arrow D. Practically I prefer to rotate the work as indicated by the arrow D and feed the tool along the line A B C.

The surfaces 47 and 48 can also be formed by casting the rings to the proper shape at the outset by one operation. Also the rings may be formed as blanks and then form surfaces 47 and 48 in an ordinary boring mill by making templets of the proper curve on a section made by a plane containing the axis that will give straight line elements in the direction of the nozzles and machining these surfaces to the templets. Another method is to have agnide made for the tool head so arranged as to profile the required surfaces by giving the tool the proper relation of radial feed and axial feed in a plane containing the axis.

The rings having been machined and brought to the sections 21 and 22" in Fig. 8, they are next to be slotted. The outer ring 21" is clamped in the saddle jaws 41 and 42 by means of the bolts 43. A milling cutter is then fed forward in the direction indicated by the arrow E in Figs. 9, 10 and 11. Relatively to the ring this is the same direction in which the tool 29 was fed to its work. It is the direction for which the nozzle lining surface 48 has straight line elements. In this way the oblique slots 49 are cut and these are of such a depth that they intersect the circumferential slots 51 lying between the flanges 40 and 38. Accordingly at 50 there are rhomboidal holes through the ring. After one slot 49 is cut in the manner described, the ring 21"is rotated in the saddle 41-42 a suitable distance and the next slot 49 is cut in the same way and- S0 011,

The inner ring 22 has the slots out in exactly similar manner, as indicated in Fig. 12. It is to be noted that the arrows E and E are opposite to each other, comparing Figs. 9 and 12, because in these two figures the two rings 21 and 227" are turned apart from each other.

The slots for receiving the blades can also be cut by reciprocating a slotting tool of the proper width along the direction A B C shown in Fig. 5, holding the rings stationary meanwhile, then rotating the rings the proper angular distance to cut the next slot and so on.

The blades or partitions 52 are to be used between the rings 21" and 22 to form the complete nozzles. Each blade 52 is cut from a. bar of steel having rectangular crosssection. The ends are beveled as shown in Fig. 15 and notched at 53 and 55 leaving slot filling portions 54 and 5.7. The part 56 at the bottom of the notch 55 is rounded. These blades 52 are then ins troduced in the slots 49, the arrangementbeing as shown in Fig. 14 which shows the blades in longitudinal section on the line 14 in Fig. 16. Thus, between the rings and the blades the nozzles 60 are formed with straight bounding elements and with expanding cross-section as is seen by comparing the dotted lines 61 and 62 in Fig. 14. The parts 54 and 57 filling the slots give a smooth inside surface for the nozzles. Where the edges of the blades 52 project through the bottoms of the slots 49 into the circumferential slots 51, said edges are headed or riveted down into the slots 51 soas to rigidly to unite the elements to form the completed nozzle ring.

' This construction of aturbine nozzle permits the useofthe most suitable metals for the rings and plates, the fabricationdoes this object. The assemblyof the nozzle is Therings are clamped in their proper relative positions and the plates an easy matter.

inserted lengthwise and riveted, thus assembling and uniting all the parts of the complete nozzle ring in a single unitary rigid structure.

This application is a continuation in part of my application Serial No. 156,835, filed March 23, 1917, (Patent No. 1,266,973, dated May 21, 1918);

The term ring in the specification and claims is intended to cover a complete ring or a segment thereof. It will be evident that certain operations or steps indicated in the specification and claims may have their order varied. For example the nozzle lining surfaces 47 and 48 may be machined before or after the circumferential slots 51 are cut.

I claim:

1. The method of forming a turbine nozzle lining surface on a ring blank which consists in moving the ring blank around its axis and moving a cutting tool to engage said ring blank along a line oblique and non-intersecting to said axis, one of said movements being a feeding movement, and the other a cutting movement.

2. The method of forming a turbine nozzle lining surface on a ring blank suitable for engagement with straight parallel edged blades to form obliquely directed nozzles, which consists in engaging a cutting tool with said ring blank, rotating said blank about its axis, and feeding said tool in the intended direction of the nozzles, whereby the elements of said surface parallel to that direction will be straight lines.

3. The method of preparing a turbine nozzle lining surface on a ring blank suitable for engagement with straight parallel edged blades to form obliquely directed nozzles, which consists in engaging a cutting tool with said ring blank, rotating said blank about its axis, feeding said tool in the intended direction of the nozzles, whereby the elements of said surface parallel to that direction will be straight lines, and slotting the nozzle lining face of said blank in the same direction to receive the edges of the blades.

4. The method of forming turbine nozzle lining surfaces on an inner ring blank and an outer ring blank, which consists in bringing said blanks into the same planewlth a It maybe preferable to common axis, rotating them 1 around said axis, engaging them with a cutting tool of the same width as the intended radial width of the nozzles and feeding said tool through between said rings in the intended direction of the nozzles, such direction being oblique and non-intersecting to the axis.

5. The method of preparing turbine nozzle lining surfaces on an inner ring blank and an outer ring blank, which consists in bringing saidblanks into the same plane with a common axis, rotating them around said axis, engaging them with a cutting tool of the same width as the intended radial Width of the nozzles, I feeding said tool through between saidrings in the intended direction of the nozzles, such direction being oblique and non-intersecting to the axis, and slotting sald blanks on their nozzle lining faces in the same dlrectlon to recelve the edges ofthe blades.

6. The method of making a turbine nozzle structure, which consists in forming a ring blank, boring the same with a tool fed in a plane containing the axis of the ring, and also with a tool fed in a direction oblique and non-intersecting to the axis,

slotting the ring in the same last mentioned direction, and fitting straight parallel edged blades in said slots.

7 The method of making a turbine nozzle structure, which consists in forming a ring blank and boring the same with a tool fed in a plane containing the axis of the ring and also to form the nozzle lining surfaces with a tool fed in a direction oblique and non-intersecting to the axis.

8. The method of making a turbine nozzle structure, which consists in forming a ring blank, slotting the same circumferentially in a boring mill, forming a nozzle lining surface by boring with a tool fed in a direction oblique and non-intersecting to the axis of the boring mill, slotting the nozzle lining face of the ring in the same last mentioned direction making these slots so deep that they intersect the circumferential slot, fitting straight parallel edged blades in said slots and riveting over the edges of the blades where they project into the circumferential slot so as to unite the ring and blades rigidly together.

9. The method of making a turbine nozzle structure, which consists in forming an inner ring blank and an outer ring blank, then in a boring mill ciroumferentially slotting the inner blank on the inside and the outer blank on the outside and forming nozzle lining surfaces by further boring with a tool engaging both said blanks and fed between them in a direction oblique and non-intersecting to the axis of the mill, then slotting the nozzle lining faces of the rings in the same last mentioned direction, making these slotsof a depth to intersect the circumferential slots, fitting straight parallel edged blades in the oblique slots, and riveting over the edges of the blades Where they'project into .the circumferential slots so as to unite I the rings and blades in a rigid nozzle structure.

10. The method of making a turbine nozzle structure which consists in forming a ring with a nozzle lining surface such that it Will have straight line elements in a direction parallel to the direction of the nozzles and straight slots of uniform depth in that direction, and fitting straight parallel edged blades in such slots.-

, 11. The method of making a turbine nozzle structure which consists in forming a ring with a nozzlev lining surface such that it will have straight line elements in a direction parallel to thedirection of the nozzles,

Copies of this patent may be obtained for slotting the ring, in the same direction and fitting straight parallel edged blades in the slots.

12 The method of making a turbine nozzle structure which consists in forming a JOHN F. METTEN.

five cents each, by addressing the Commissioner of Patents, Washington, I). C. 

